BEIJING -- The death toll pushed inexorably higher Tuesday in the aftermath of a massive earthquake in China, with state media saying 12,000 died in one province alone.

The 7.9-magnitude quake struck southwestern China Monday afternoon, collapsing buildings and burying tens of thousands of people. The initial shaking was followed by more than 30 smaller jolts within 24 hours.

Li Chengyun, vice governor of Sichuan province, said 12,000 people had died in that province alone and more than 26,000 were injured, CNN reported. Some 3.5 million homes were destroyed.

The official Xinhua news agency reported more than 18,645 people buried and 3,629 killed in the city of Mianyan, near Wenchuan County, the epicenter of the temblor.

About 17,000 Chinese soldiers joined a huge relief effort and 34,000 armed forces were traveling by all modes of transport -- even walking -- to the southwestern province.

Xinhua, quoting a witness, reported the road from Dujiangyan, northwest of the provincial capital Chengdu, to Wenchuan remained blocked by rocks and mud slides, hampering relief efforts.

Chinese Premier Wen Jiabao, who arrived in the province, ordered the waiting troops to reach the epicenter even if that required walking, Xinhua reported.

China Daily reported the quake devastated several small cities and towns set against the steep and forested hills northwest of Chengdu.

The quake knocked out telephone networks in Chengdu, leaving the provincial capital's 10 million people without communications.